Thanks for that Girvin.
In fact my query does have the quotes around field names.
I've included it at the bottom here.
I haven't noticed any difference between " ` " (backtick) or either
usual type of quotation mark either.
I appear to be using the MySQL JDBC driver, com.mysql.jdbc.Driver,
which *may* be new since I last ran this query, so it might be Java
causing the problem.
It'll get to the top of my todo list eventually 
Mark Stanton
One small step for mankind...
SELECT LTRIM( CONCAT( `people`.`Title`, ' ',
LTRIM( `people`.`Firstname` ), ' ',
LTRIM( `people`.`Surname` ) ) ) AS `PersonName`,
`people`.`PersonId`, `issues`.`iId` AS `iiID`, `issues`.`Issue`,
`people`.`LastIssue`, `subscription`.`iId` AS `subiId`,
`subscription`.`Type`, `subscription`.`AdType`,
`subscription`.`Delivery`, `subscription`.`Issues`,
`subscription`.`StartingAt`, `address`.`Company` AS `Co`,
`Address1` AS `Address1`, `Address2`, `Address3`, `City`,
LTRIM( `Area` ) AS `Area`, `Country`, `PostalCode`,
`sent`.`iId` AS `SendId`, `sent`.`NumberSent`,
LEFT( `textvalues`.`Text`, 1 ) AS `Text`,
LastIssue=Issue AND Type=2 AS RenewalDue
FROM `people`
JOIN `subscription` ON `people`.`iId` = `subscription`.`iPeopleId`
JOIN `sent` ON `sent`.`iSubId` = `subscription`.`iId`
JOIN `issues` ON `sent`.`iIssueId` = `issues`.`iId`
JOIN `address` ON `people`.`iId` = `address`.`iParentId`
JOIN `textvalues` ON `textvalues`.`Id` = `subscription`.`Type`
WHERE `issues`.`Issue` = '74' AND `sent`.`sent` = 0 AND
`Delivery` = 1 AND `textvalues`.`Field` = 'CBOSUBTYPE'
ORDER BY `FirstName`, `Surname`